The authors have found that compulsory training using treadmill running increases pancreatic weight, protein content, and enzyme activity in hypertrophied acinar cells in rats. The purpose of the present study was to investigate the effect of voluntary running exerise on the exocrine pancreas in rats. Female F344 rats were divided into control, compulsory training, and voluntary training groups. The compulsory trained rats were exercised for 60 min on a treadmill (final speed, 35 m/min), 5 days a week, for 8 weeks. The voluntary trained rats were exercised on a voluntary basis on a wheel ergometer with a load of 30% of their body weight every day. Mean running distance for the voluntary training group was 5.2±1.0 km/day. Final body weight for the compulsory and voluntary training groups was significantly lower than for the control group. Soleus muscle weight and citrate synthase activity of the plantaris muscle for the compulsory and voluntary training groups were significantly higher than for the control group. Pancreatic wet weight, protein content, and amylase and lipase activities for the compulsory and voluntary training groups were significantly higher than for the control group. Pancreatic wet weight, protein content, and amylase and lipase activities for the compulsory and voluntary training groups were significantly higher than for the control group. Total DNA content of whole pancreas in the voluntary training group was significantly higher than for the control and compulsory training groups. Electron micrographs revealed that acinar cells obviously hypertrophied and zymogen granules increased in the compulsory and voluntary training groups rats compared with the compulsory group. These results suggest that voluntary training increases pancreatic weight and protein content in hypertrophied and/or hyperplasic acinar cells, which in turn increases synthesis and the storage of exocrine pancreatic enzymes.

In this study, we investigated the effects of prolonged voluntary running training on bone mass in the tiba of growing male SD rats. At 5 weeks old, the rats were divided into 4 groups : group 15 VE (n=7) exercised voluntarily on a running wheel for 10 weeks from 5- to 15-weeks old ; group 35 VE (n=7) exercised voluntarily on a running wheel for 30 weeks from 5- to 35-weeks old ; in groups 15SC (n=6) and 35 SC (n=5), rats were housed individually in normal plastic cages for the same periods as groups 15 VE and 35 VE, respectively. At the end of each experimental period, the right tibia from each rat was used for bone- mass analysis using peripheral quantitative cumputed tomography (pQCT) . The evaluated portions were the proximal methaphysis and the diaphysis, with total, cortical, and trabecular data from these portions being obtained as volumetric bone mineral content (vBMC) and volumetric bone mineral density (vBMD) . The results indicated that 1) although voluntary running distance tended to decline during the later period (1635 wk old) in 35 VE rats, some mean values obtained for bone mass parameters using pQCT were significant greater in 35 VE than in 35SC ; 2) the mean values from those parameters in 15 VE were not significantly different from those in 15 SC. These results suggest that the continuation of voluntary exercise may be important for bone- mass enhancement in rat tibia.

The purpose of this study was to assess the status of nutrients intake in male Japanese collegiate athletes. Each 20 of baseball (B), soccer (S), volley ball (V), and long distance (L) athletes participated in this study. The B, S, and V athletes lived by themselves, whereas the L athletes lived in an athletes dormitory with provided meal. The nutritional status was assessed for 2 days. Mean energy intakes in the B, S, V, and L groups were 43.6, 53.7, 47.0, and 55.0 kcal/kg body weight, respectively. Mean protein intakes were 1.2, 1.6, 1.3 and 2.4 g/kg, respectively. In B athletes, skipping of breakfast was recognized frequently. Most of micronutrients intakes in the B, S, and V groups were less than the recommended dietary allowances for athletes. We suggest that a provided meal system is a better system for collegiate athletes and more nutritional education is necessary for Japanese male collegiate athletes, in particular, those living by themselves.